The above referenced applications have dealt in the main with the mechanisms for vision controlled positioning and checking of the parts to be assembled, with automotive sheet metal components being the particular area most disclosed. This application goes into more detail on the intelligence functions that can be brought to bear on serial production of components, as well as singular components. It also describes in more detail the standard modules of the system, and the standard assembly systems that result, including an extension to aircraft assembly operations, and particularly the riveting operations for attachment of the airplane's "skin".
As pointed out in my previous applications, the overall goal of the invention is to provide a far higher degree of flexibility for factories--even as here disclosed allowing them to become "dual use" factories (that is for example capable of making aircraft in time of war, but using substantially the same tool and its sensing control systems for making sheet metal car bodies during peace).
This invention further elaborates on the concept first described in the reference co-pending application (ref. 7), which discloses the advantages of rapidly and electro-optically obtaining substantial amounts of accurate data concerning the parts produced, and providing the data base so created to other process steps within the overall process of manufacture.
There is a need in the industry to assure that the pieces to be welded together to make a sheet metal car body assembly and other similar assemblies and other industries, such as white goods, tractors, trucks, etc. contain the correct features and overall shapes, that they are in sufficient position to be welded, that they have been clamped together correctly for welding or other joining purposes, and that they are in the correct configuration and shape for welding. In addition, the robots or other welding automation used to make the welds also need to be confirmed in their location if possible before executing their tasks or sensor-wise caused to go to the correct location. In today's lines with fixed hard tools locating the parts in fixed clamps coming down, with either manual load of the panels, or automatic load, and robotic and fixed guns located programmably moving to different locations or the use of fixed guns within the tool to tack down the parts, there is very little sensory processing within the tool. The only thing in common use, to my knowledge, is limit switches, which essentially assure that the clamps have gone down, and in some cases that the parts are more or less in place. These switches are typically inductive types proximity switches or mechanical contact switches.
For the assurance that the assembly has been correct after welding, parts have been put on manual checking fixtures after welding, checked by CMM, or in some elaborate installation, checked by in-line optical gaging systems such as those built by Diffracto and Perceptron in the U.S.
This application is aimed at increasing the sensory capabilities of the tooling and related assembly systems, and follows form several previous applications by the inventor referenced above. Electro-optical sensors are preferably used for the measurement of tool and part position, as well as force sensors in certain embodiments for the determination of forces rendered by the clamping or welding devices. In this application, two other forms of sensors are depicted; namely the use of a 3D range imaging sensor device, and a use of miniature TV and/or stereo, or light section triangulation sensors located on the tool base. These are in place of, or addition to, the photogrammetric sensors.
The cost of design and construction and the time involved therefore for the fixture tools needed to assemble the structure and other parts of cars, aircraft, or other three dimensional objects constitute huge cost burdens to the launching of any new product in these areas. "Tooling" (also including form tools such as dies and molds) for a new car can cost several hundred million dollars, for just the physical design and build of the "hard" tools, not including any robots or other automation, nor the labor of using the tools, or of trying to adjust them after the fact. The situation in the car business is of late compounded by shorter product life cycles and the necessity to make old parts for a longer period of time, even after the plant itself has changed over to some new model.
Using today's technology, no more than 10% of the assembly tooling used for the previous model is reusable. By going to modular and standardized components of the invention, coupled with their intelligent control, it is estimated that nearly 90-95% may become usable. This has huge capital life cycle cost implications, on top of which is the huge improvement in quality and production efficiency offered by the invention, which can check its own work as desired to assure all conditions are correct and develop data bases from which subsequent tools can be developed, and to generate intelligence of the process which can be used to decrease down time and reduce scrap, and improve production efficiency at all levels of the enterprise.
There is a need in the industry to assure that the pieces to be welded together to make a sheet metal car body assembly and other similar assemblies and to make sheet metal assemblies in other industries, such as white goods, tractors, trucks, etc. contain the correct features and overall shapes, that they are in sufficient position to be welded, that they have been clamped together correctly for welding or other joining purposes, and that they are in the correct configuration and shape after welding. In addition, the robots or other welding automation used to make the welds also need to be confirmed in their location if possible before executing their tasks or their positions sensed and then so controlled so as to go to the correct location.
In today's lines with fixed hard tools locating the parts in fixed clamps with either manual load of the panels, or automatic load, and robotic and fixed guns located programmably moving to different locations or the use of fixed guns within the tool to tack down the parts, there is very little sensor processing within the tool. The only thing in common use, to my knowledge, is limit switches, which essentially assure that the clamps have gone down, and in some cases that the parts are more or less in place. These switches are typically inductive types--proximity switches or mechanical contract switches.
For the assurance that the assembly has been correct after welding, parts have been put on manual checking fixtures after welding, checked by CMM, or in some elaborate installation, checked by in-line optical gaging systems, such as those built by Diffracto and Perceptron in the U.S.
This application is aimed at increasing the sensory and reconfigurability capabilities of the tooling, and follows from several previous applications by the inventor referenced above.
Much of the prior art, so to speak, is my own, and referenced above. Some of these cases have been granted or published in some form.
Additional prior art in, directly applicable to these particular areas, are the group of patents filed by Nissan Motor Car Co. of Japan. Those I am aware of are U.S. Pat. Nos. 5,005,277; 5,010,634, 4,691,905; and 4,880,307; U.K. #2,234,606 A, as well as various Nissan press releases, etc., on their "Intelligent Body Assembly System", (IBAS).
Another reference, filed by McGee et al. (GMF Robotics Corp), U.S. Pat. No. 4,942,539 or PCT/US89/05727 is directed primarily at the use of determination of 3D orientation of objects from vision data, particularly for the assembly of completed major car sub-assemblies.
Other prior art references in the general field of car body assembly are:
1. Sciaky, U.S. Pat. No. 4,654,505. PA0 2. Alborante (Comau), U.S. Pat. No. 5,115,115 and 5,064,991. PA0 3. European Patent 87100612.8 or EP 0261 297, by Kurt Jack. PA0 4. Inoue et al. (Toyota) U.S. Pat. No. 4,779,336.
It is an overall goal of the invention to allow much more rapid response to market demands by allowing accurate tools to be built of modular components that could be rapidly assembled and verified, using the sensing systems of the invention, and as well tools that can be increasingly "smart", or "intelligent", allowing a variety of different functions to be accomplished, allowing the operation to much more rapidly home in on the idealized settings for various locator positions, clamps, and other devices that are used within tools to assure the maximum possible quality and productivity, using the parts that are being provided to the tools, which may themselves be less than perfect, and require accommodation at the tool.
It is also an overall goal of the invention to provide means for gathering and generating data bases using sensing systems, which will allow the feed forward of data taken in the tool to further welding, or other assembly operations, and to feed back the data to previous assembly or welding operations, or even to press plants and other functions.
It is a further goal of the invention to provide a means to develop the process in the most optimum manner, such that the further work with the same or similar tools on related parts, can be more optimally designed through use of the data base generated, and its feedback to the CAD design system of both the parts and the tools. By providing the mechanism for assurance of quality within the tool, the various combinations and perturbations of the initial tool location and clamping, welding and other settings can be made, while still assuring that acceptable parts leave the tool. This then allows an automated development of the tooling process, and serves to provide data for subsequent processes with the same tool, similar tools, similar parts, or with other similar processes.
It is also a goal of the invention to disclose communication of data from the sensor system of the invention at a particular tool location to other parts of the immediate work assembly system, such as other tooling stages in a body side line, as well as to other feeder plants, or post-assembly operations that could use the dimensional and other weld data obtained, and to further communicate to other portions of the enterprise the data for the incorporation into the design systems, and for use in the maintenance of both the instant tool of the invention, as well as in those processes ahead of it that could be causing the problems that are detected in the tool.
It is also purpose of this invention, where possible, to provide systems to assist in the reduction of the flange width required for welding. This can effect a major weight and cost saving in vehicle manufacture.
It is also a goal of the invention to provide systems which can produce acceptable assemblies with marginal or defective incoming constituents parts, by optimizing their interrelationship to produce where possible an acceptable (and at the very least, flag the assembly as defective and reject it if such optimization is not possible). The invention herein further addresses the learning from sequential runs of parts through the tool. This is particularly aimed at the building up of the data base, as mentioned, and the perturbation of various parameters. The goal is reduction of variability of the parts, and optimizing the assembly for a given group of constituent parts.
It is also a goal of the invention to provide data to assist in design of the next set of tools, for example aiding in the proper choice of clamping locations based on studies of perturbations in location of those locations used.
It is a further goal to provide, using vision systems and other sensor devices as appropriate, checks within the tool cell for missing holes in parts, incomplete metal, misloaded parts that may not be seated correctly in the tool, and for sensing the quality of welds optically to the level that this possible. (Also described in reference 1.) In some cases, these functions can be performed by the same 3D camera or other sensor system that determines the location of the parts and the tooling locators.
It is also a goal of the invention to provide for the modification of the part in the tool, as a result of sensed data. One version of this includes the laser based bending of the part, due to internal stresses. Another includes laser cutting of holes, slots, tabs, edge trimming and other activities. Drilling and riveting is also contemplated, as are additional machining or assembly operations within the tool.
These and other goals of the invention are achieved as described in the description which follows.